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I had just tested my first monitor, which results in the following error regarding the suggestion in How to define conditions for state-machines in roby?

unfortunately i ran into a runtime error, i don't know whether this is a bug or if i misuse the monitor...

16:28:27.564 (Roby) = failed emission of the weak_signal event of Pipeline::Detector:0x71f5cf0
16:28:27.564 (Roby) = Backtrace
16:28:27.564 (Roby) |
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/task.rb:663:in `emitting_event'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/task_event_generator.rb:46:in `emitting'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/event_generator.rb:628:in `emit_without_propagation'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1017:in `block (2 levels) in event_propagation_step'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:648:in `propagation_context'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1015:in `block in event_propagation_step'
16:28:27.564 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:559:in `block in gather_propagation'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:648:in `propagation_context'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:559:in `gather_propagation'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1014:in `event_propagation_step'
16:28:27.565 (Roby) |/home/auv/dev/tools/roby/lib/roby/execution_engine.rb:783:in `block in event_propagation_phase'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:761:in `gather_errors'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:779:in `event_propagation_phase'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1426:in `process_events'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1940:in `block (2 levels) in event_loop'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/support.rb:176:in `synchronize'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1939:in `block in event_loop'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1917:in `loop'
16:28:27.565 (Roby) /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1917:in `event_loop'
16:28:27.565 (Roby) | /home/auv/dev/tools/roby/lib/roby/execution_engine.rb:1797:in `block (3  levels) in run'
16:28:27.565 (Roby) =

Don't know whether this is a bug, or if i had miss-used the monitor... here is the action_state_machine i'm using:

183     describe("Find_pipe_with_localization").
184         optional_arg("check_pipe_angle",false)
185     action_state_machine "find_pipe_with_localization" do
186         find_pipe_back = state target_move_def(... some long stuff here ... )
187         pipe_detector = state pipeline_detector_def
188         pipe_detector.depends_on find_pipe_back, :role => "detector"
189         start(pipe_detector)
190
191         pipe_detector.monitor(
192             'angle_checker', #the Name
193             pipe_detector.find_port('pipeline'), #the port for the reader
194             :check_pipe_angle => check_pipe_angle). #arguments
195             trigger_on do |pipeline|
196                 angle_in_range = true
197                 if check_pipe_angle
198                     angle_in_range = pipeline.angle < 0.1 && pipeline.angle > -0.1
199                 end
200                 state_valid = pipeline.inspection_state ==  :ALIGN_AUV || pipeline.inspection_state == :FOLLOW_PIPE
201                 state_valid && angle_in_range #last condition
202             end. emit pipe_detector.success_event
# for non-monitor use, this works if the above is commented out
203 #        forward pipe_detector.align_auv_event, success_event
204 #        forward pipe_detector.follow_pipe_event, success_event
205
206         forward pipe_detector.success_event, success_event
207         forward pipe_detector,find_pipe_back.success_event,failed_event #timeout here on moving
208     end
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5
  • $\begingroup$ are you sure that the first line is not cut prematurely ? If I look at Roby's code, the error comment is much longer (and more informative) $\endgroup$
    – sylvain.joyeux
    Commented Jun 17, 2014 at 12:46
  • $\begingroup$ the only line above is: 11:10:24.775 (Roby) Internal Error: #emit_without_propagation emitted a LocalizedError exception. This is unsupported and will become a fatal error in the future. You should usually replace raise with engine.add_error $\endgroup$
    – Matthias Goldhoorn
    Commented Jun 20, 2014 at 9:15
  • $\begingroup$ OK, got it. There's a bug in the display of the exception. The code does set a pretty specific message but it does not get displayed by EmissionFailed#pretty_print. Looking at the code line, it appears that the event gets emitted but the task is not started $\endgroup$
    – sylvain.joyeux
    Commented Jun 23, 2014 at 11:43
  • $\begingroup$ Okay, even so, how it can be happen that the (an) event is emmited in the above code? The code simply emmited the success_event of the pipeline detector which should run..?! $\endgroup$
    – Matthias Goldhoorn
    Commented Jun 23, 2014 at 11:45
  • $\begingroup$ The state machine is not emitting the event that is causing your problem. Something else is. $\endgroup$
    – sylvain.joyeux
    Commented Jun 23, 2014 at 14:49

1 Answer 1

Reset to default
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Apart from the error message that is very unspecific (look at my comment to the question), the event that is causing the fault (weak_signal) is not part of the state machine. I guess that there is something else going on here that has no relationship with the monitor at all.

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2
  • $\begingroup$ What i wondering about, ist that a) in the simulation this monitor works perfectly, and b) if i not using the monitor, and the forward directly the setup works well too..., suggestions? $\endgroup$
    – Matthias Goldhoorn
    Commented Jun 23, 2014 at 11:57
  • $\begingroup$ Have you looked at the event log ? To me, it looks like some event gets forwarded to a task that is not yet started. I start to think that it is something that Roby should ignore and filter out instead of creating an error, would be a lot more usable than the current situation and not change semantics so much. $\endgroup$
    – sylvain.joyeux
    Commented Jun 23, 2014 at 13:00

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